Screening level analysis for monitoring pesticide in river water using a hydrological diffuse pollution model with limited input data.

To predict rice-farming pesticide concentrations in river water with imprecise model inputs for screening-level analysis, a basin-scale runoff model was developed. The Monte Carlo method was applied to create estimates of input data regarding agricultural work schedules and parameters for pesticide decomposition and sorption in solids and water. The prediction accuracy of the model was evaluated when used with non-optimised pesticide parameters; the model was calibrated using hydrological data alone without reference to observed pesticide concentration data. Overall, predictions for the pesticide concentrations were successful within order-of-magnitude accuracy. The pesticide rankings according to the predicted concentration roughly agreed with those observed. The success of screening-level analysis indicates that the model prediction can help in selection of pesticides to be monitored and in determining the monitoring schedule for the river basin.     

分布式水文模型对水质监测数据的补充及污染源分析

水质现状监测对水环境影响评价、水环境治理具有重要作用。目前,水质现状监测数据存在监测频率低、监测难度大、影响因素复杂及信息化程度低等问题。为此,采用了分布式水文模型对水质监测数据进行补足,并追根溯源分析污染物来源。以都匀市剑江河流域为例,基于水文气象、下垫面数据及仅有的2010-2014年的四个断面不同步的水质数据,建立SWAT分布式水文模型模拟总磷污染物。结果表明,使用分布式水文模型不仅可以补足剑江河流域四个监测断面同期的总磷数据,还可以追根溯源得出该流域总磷污染主要来源于面源污染,同时可以分析出面源污染的空间分布情况以及不同污染类别的占比,该流域中肥料流失为主要污染源,尤其是丰水年的污染占比高达近66%。     

Simultaneous estimation of model parameters and diffuse pollution sources for river water quality modeling.

Diffuse pollution sources along a stream reach are very difficult to both monitor and estimate. In this paper, a systematic method using an optimal estimation algorithm is presented for simultaneous estimation of diffuse pollution and model parameters in a stream water quality model. It was applied with the QUAL2E model to the South Han River in South Korea for optimal estimation of kinetic constants and diffuse loads along the river. Initial calibration results for kinetic constants selected from a sensitivity analysis reveal that diffuse source inputs for nitrogen and phosphorus are essential to satisfy the system mass balance. Diffuse loads for total nitrogen and total phosphorus were estimated by solving the expanded inverse problem. Comparison of kinetic constants estimated simultaneously with diffuse sources to those estimated without diffuse loads, suggests that diffuse sources must be included in the optimization not only for its own estimation but also for adequate estimation of the model parameters. Application of the optimization method to river water quality modeling is discussed in terms of the sensitivity coefficient matrix structure.     

基于SWAT的灌区分布式水文模型——Ⅰ.模型构建的原理与方法

针对中国南方丘陵水稻灌区水文特点,在对自然流域水文模型SWAT改进的基础上,构建了灌区分布式水文模型,改进了SWAT的灌溉水运动模块、稻田水分循环模块、稻田水量平衡各要素和产量模拟的计算方法,改变了陆面水文过程的计算结构,增加了渠系渗漏模拟模块及其对地下水的补给作用、塘堰的灌溉模块等。以湖北省漳河灌区内的一个闭合小流域为例,对构建的灌区分布式水文模型进行校正和验证,模拟结果显示,该模型适合于水稻灌区水分循环的模拟。     

葛洲坝2号船闸安全监控模型研究

葛洲坝２号船闸担负大部分货运和部分客运过坝任务，下闸道的运行性状直接影响２号船闸整体安全和正常工作，因面在建立数学模型和相应的监控指标时，选择２号船闸下闸首作为整体作用效应，采用三维有限元计算模型，用有限元水平变形为控制量，为更准确地反映闸首的整体作用效应，采用三维有限元元计算模型，用有限元分别计算出各主要影响因素的效应量，然后进行叠加，建模中的主要技术问题是坝基物性参取值问题，其取值是与计算分析     

Monitoring of pH inhibition on microbial activity in a continuous flow reactor by pseudo toxic concentration (C(PT)) concept and time delay model.

The pseudo toxic concentration (C(PT)) concept was introduced as a quantification method to describe pH as an inhibitor concentration. In this research, the applicability of the C(PT) concept model for the detection of pH inhibitions was expanded for a continuous flow activated sludge reactor. A pilot equipped with an inhibition detection system was installed. Inhibitory wastewater was injected for 1 h and the relative activity was calculated by the maximum respiration rate. At the same time, the coefficients for the C(PT) concept model were estimated. At the dynamic conditions, the estimated relative activity by the C(PT) concept model showed time lag compared to the measured one. However, the time lag problem was successfully resolved by introducing a transfer function into the C(PT) concept model. The C(PT) concept model combined with a transfer function (C(PT) + TF model) successfully tracked the variation of the relative activity under dynamic conditions. The C(PT) + TF model could detect 50% inhibition faster than the respirometry based method by approximately 10 min. Moreover, it had additional advantages such as being inexpensive, easy to install and simple to operate. In conclusion, the C(PT) + TF model was an effective and convenient detection method of pH inhibition.     

Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration.

This study was conducted to compare the performance of a continuous-flow stirred-tank reactor (CSTR) and an anaerobic sequencing batch reactor (ASBR) for fermentative hydrogen production at various substrate concentrations. Heat-treated anaerobic sludge was utilized as an inoculum, and hydraulic retention time (HRT) for each reactor was maintained at 12 h. At the influent sucrose concentration of 5 g COD/L, start-up was not successful in both reactors. The CSTR, which was started-up at 10 g COD/L, showed stable hydrogen production at the influent sucrose concentrations of 10-60 g COD/L during 203 days. Hydrogen production was dependent on substrate concentration, resulting in the highest performance at 30 g COD/L. At the lower substrate concentration, the hydrogen yield (based on hexose consumed) decreased with biomass reduction and changes in fermentation products. At the higher substrate concentration, substrate inhibition on biomass growth caused the decrease of carbohydrate degradation and hydrogen yield (based on hexose added). The ASBR showed higher biomass concentration and carbohydrate degradation efficiency than the CSTR, but hydrogen production in the ASBR was less effective than that in the CSTR at all the substrate concentrations.     

Simulation of nitrification of municipal wastewater in a Moving Bed biofilm process: a bottom-up approach based on a 2D-continuum model for growth and detachment.

This paper presents a complete mathematical model of a Moving Bed biofilm process for waste-water treatment, in particular for the nitrification process. The model is based on a bottom up approach adopting a multidimensional model for the biofilm growth and metabolism and a global mass balance model for the whole reactor. The model shows that oxygen is limiting the amount of biomass involved in the nitrification process. Furthermore, it suggests the existence of an optimal amount biomass for an optimal reactor turnover rate. Studies of two specific new suspended carriers show that the model output is dependable on the geometry of the carrier, and to a satisfactory extent agreeable with measurements.     

Effect of co-substrate, biomass and sulfate concentration on the performance of a control strategy used to determine the anaerobic stage length of an anaerobic/aerobic SBR degrading p-nitrophenol.

The effect of the p-nitrophenol to propionic acid ratio, the biomass concentration, and the presence of sulfates on the performance of a control strategy of an anaerobic/aerobic SBR degrading p-nitrophenol was studied. The duration of the anaerobic stage was controlled by an algorithm based on the on-line measurement of the oxidation-reduction potential, which indicates the end of the reduction of p-nitrophenol to p-aminophenol. It was observed that no significant influence on the performance of the algorithm was found when the co-substrate, the biomass concentration and the presence of sulfates were varied, indicating the robustness of the control strategy. Only for the case when a low concentration of cosubstrate was used, was there no transformation of p-nitrophenol.